flat/weak battery on- W-reg- S3 so removed and put in a brandnew one,car started up but now there is a misfire when driving.
Car still pulls good but you can tell its holding back and there is a misfire aswell.

Put on vag-com and it came up with lambda sensor.
low supply voltage and relay j231 (j231 i think ) Electrical malfunction.

anyway once these faults were cleared......drove car around a few miles and re-checked with vag-co and it showed no faults.

I think the previous faults could be linked to the flat battery it had before.

ANY IDEAS.? even after a day of driving there are no fault codes.